An exposure apparatus used in a process of manufacturing devices, such as a semiconductor device and a liquid crystal display device, has a stage which moves a master such as a mask or reticle, or a substrate to be exposed such as a semiconductor wafer or glass substrate (these will be generally referred to as substrates hereinafter). The stage is supported (guided) by, e.g., a hydrodynamic bearing.
As a stage apparatus which uses a conventional hydrodynamic bearing, for example, one as shown in Japanese Patent Laid-Open No. 10-256111 is available (see FIG. 6). Referring to FIG. 6, an X stage 51 and Y stage 54 are movable along a surface plate 55, and the bottom surfaces of the X stage 51 and Y stage 54 are supported by hydrostatic bearings (hydrodynamic bearings). The Y stage 54 can move in the Y direction along a stationary guide 52, and the side surface of the Y stage 54 is supported by hydrostatic bearings. FIG. 7 is a sectional view, seen from the positive direction along the Z-axis, of a surface that opposes the stages 51 and 54 and surface plate 55. The X stage 51 is supported by hydrostatic bearings 53b to be in non-contact with the surface plate 55, and the Y stage 54 is supported by hydrostatic bearings 53c and 53d to be in non-contact with the surface plate 55 and stationary guide 52. The X stage 51 and Y stage 54 are provided with magnet units 56a, 56b, and 56c which apply a preload force to stabilize the gaps of the hydrostatic bearings.
As a stage apparatus that uses a hydrostatic bearing in a vacuum atmosphere, one as shown in, e.g., Japanese Patent Laid-Open No. 2002-257138, is available. Japanese Patent Laid-Open No. 2002-257138 discloses a mechanism in which a movable body is supported in a high vacuum by using a static pad, and a labyrinth portion having an exhaust groove is formed around the static pad.
When the magnet units 56a are arranged only near the centers in the longitudinal direction of hydrostatic bearing attaching plates 54a, as shown in FIG. 7, the acting point of the repulsive force of hydrostatic air and those of attracting forces generated by the preload magnet units are different, and the bearing surfaces of the hydrostatic bearing attaching plates 54a and surface plate 55 deform undesirably. This deformation partially decreases the gap between the hydrostatic bearings 53d and surface plate 55, and the hydrostatic bearings 53d and surface plate 55 may come into contact with each other in the worst case.
In recent years, the stage apparatus is sometimes used in a non-air atmosphere such as a vacuum atmosphere. A labyrinth partition is formed around a hydrostatic bearing so that air will not leak outside. Therefore, the attaching plate or stage becomes large, and its deformation amount also increases accordingly. In addition, degassing from a preload force biasing means which biases a preload force must also be taken into consideration.